Heat olive oil in a large saucepan over medium heat. Add onion; cook 5 minutes or until tender, stirring occasionally. Add peaches, black pepper, salt, and garlic; cook 1 minute, stirring frequently. Stir in beer and remaining ingredients, and bring to a boil. Reduce heat, and simmer, uncovered, 30 minutes. Place half of mixture in a blender. Remove center piece of blender lid (to allow steam to escape); secure lid on blender. Place a clean dish towel over opening in blender lid (to prevent spills). Process until smooth. Pour pureed mixture into a medium bowl. Repeat procedure with remaining mixture.
Note: Refrigerate sauce in an airtight container for up to 10 days.